Facile large scale synthesis of WS2 nanotubes from WO3 nanorods prepared by a hydrothermal route

Hexagonal WO3 nanorods of 5-50 nm in diameter and 150-250 nm in length have been synthesised in gram quantities by a low temperature hydrothermal route using citric acid as a structural modifier and hexadecylamine as a templating agent. The ratio of [A]/[W] play an important role on WO3 nanorods formation. These WO3 nanorods were found highly suitable as a precursor for the synthesis of a good yield of multiwalled WS2 nanotubes by reducing them with H2S at 840 °C for 30 min. The length and the wall thickness of the WS2 nanotubes could be altered by controlled reduction of the oxide precursor. The morphology, structure and the composition of the WO3 nanorods and WS2 nanotubes were characterised by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray analysis (EDX) and by selected area electron diffraction techniques (SAED).